I had read that Century Arms was converting No.4 rifles to .45 ACP using an adaptor kit and a .45 pistol magazine. The unmarked kit appears to be a Rhinelander kit. Unfortunately Rhinelander is no longer making them and one wonders how many kits Century obtained before their "demise." This was at the gunshop at Knob Creek.
To date, the only thing I have done to it is to add the front sight ears. It would appear that they sacrificed a nice condition Savage. The normal rifle magazine is replaced with an aluminum version with hole and magazine catch for the .45 magazine. It attaches in the same manner as the normal magazine. The barrel is screwed in, headspaced and fixed with a jam nut like the Savage 110 rifle. While not an original Enfield, it is an interesting variant.